I couldn't say for sure without knowing all of the details with your setup, but I would suggest that if you have installed Intel HD Graphics Driver Version 220.127.116.1129 that you try instead Graphics driver version 18.104.22.16864. See Important Note at https://downloadcenter.intel.com/download/26947/NUCs-Intel-HD-Graphics-Driver-for-Windows-10-for-Intel-NUC-Kit-NUC7i3BN-NUC7i5BN-and-NUC7i7BN.
I ran the driver update utility a couple more times as three of the drivers had not updated first time around. This gave me sound.
Then I installed the older video driver which has stopped the flicker.
You are welcome.
I wouldn't rely too heavily on the Intel Driver Update Utility. Even Intel has suggested that looking for updates on https://downloadcenter.intel.com/search?keyword=NUC7i5BNH might be a better option.
I would also suggest that if you are running a bios version lower than 47, and you are not seeing any issues relating to hyperthreading, that you don't update unless you are confident that you both need to and that other issues that seem to have emerged with some users appear to have been resolved.
I work for Intel Customer Support and I want to let you know that we are aware of screen flashing and/or flickering issue when using 4K resolutions on NUC7ixBN systems.
This issue has been reported and engineering is working on finding a solution for it, and glad your audio issue was resolved but we need to find a fix for this one as well.
I am trying to locate all community threads related to this issue to refer them back to the following one and consolidate: NUC7ixBN Screen Flashing/Flickering when using 4K resolutions <https://communities.intel.com/thread/116824> We will keep this community thread updated with any progress we make.
I apologize for any inconvenience this may have caused or is still causing and I appreciate your help and patience.
I will be locking up this thread to make sure all comments are properly tracked and followed on NUC7ixBN Screen Flashing/Flickering when using 4K resolutions